This is due to some incompatibility with newer PuTTy client versions and older SSH server versions in NMC1 products, this error message is received and access is not allowed. This will also likely affect WinSCP users since WinSCP and PuTTy share similar SSH and SCP code.

Resolution

This issue will be evaluated for a fix in products currently shipping that use NMC1. Any information regarding a firmware fix will be provided here, when available.

For the time being, it is suggested that a user use an older version of the PuTTy client, if available. Otherwise, other commonly available SSH clients may work in order to access the NMC1 device via the SSH protocol.